There are several different kinds of assessments of cardiorespiratory fitness such as timed runs, timed walks, and step tests. The different tests assess the use of different muscle groups as well as different levels of exertion. Running is more intensive than walking, and walking for a mile at a steady pace over level ground uses different muscle groups than stepping up and down repeatedly. Using multiple, different fitness assessments gives a more complete picture of the various factors that contribute to an individual's level of cardiorespiratory fitness.
